Method and apparatus for hermetically sealing a package

ABSTRACT

A method and apparatus for forming and applying closure fasteners to the gathered neck portions of bags or casings wherein the fastener is preformed from wire stock into a U shape by means of a fastener forming and applying apparatus which includes a punch and co-operating anvils operable to preform the fasteners while simultaneously applying a previously formed fastener to a gathered bag neck so as to wrap the legs of the fastener tightly about the bag neck material with the legs lying side by side and providing a tight hermetic seal.

United States Patent 1191 Keating et al.

1451 Oct.21, 1975 METHOD AND APPARATUS FOR HERMETICALLY SEALING A PACKAGE [75] Inventors: Raymond J. Keating, Bettendorf;

Lewis M. Shuh, Davenport; Roy E. Wells, Maquoketa, all of Iowa [73] Assignee: The Kartridg Pak C0., Davenport,

Iowa

1221 Filed: 061.29.1973

211 App1.No.: 410,532

Related U.S. Application Data [62] Division of Ser. No. 141,588, May 10, 1971, Pat. No.

[52] U.S. Cl 140/82; 53/138 A [51] Int. Cl? ..B21F 45/16 [58] Field of Search 29/509, 243.57, 280, 33.5; 83/580, 440; 227/90, 88; 140/82; 53/138 A,

[56] References Cited UNITED STATES PATENTS 415,621 11/1889 Collins 83/580 507,101 10/1893 Boggs 2,428,026 9/1947 lrmscher I: 227/88 2,880,419 4/1959 Tipper 53/138 A 3,368,322 2/1968 Yasui 53/138 3,377,692 4/1968 Tipper n 29/24357 3,524,242 8/1970 Odean et al. 29 24357 3,525,096 8/1970 KlBflZ 140/82 3,583,056 6/1971 Klenz 29 243,57 3,626,994 12/1971 Klenz 140 82 Primary Examiner-Lowell A. Larson Assistant E.raminer.lames R. Duzan Attorney, Agent, or Firm Lockwood, Dewey, Zickert & Alex [57] ABSTRACT A method and apparatus for forming and applying c|osure fasteners to the gathered neck portions of bags or casings wherein the fastener is preformed from wire stock into a U shape by means of a fastener forming and applying apparatus which includes a punch and co-operating anvils operable to preform the fasteners while simultaneously applying a previously formed fastener to a gathered bag neck so as to wrap the legs of the fastener tightly about the bag neck material with the legs lying side by side and providing a tight hermetic seal.

2 Claims, 12 Drawing Figures Oct. 21, 1975 Sheet 1 of 3 U.S. Patent US. Patent 0a. 21, 1975 Sheet 2 of3 3,913,628

U.S. Patent Oct. 21, 1975 Sheet 3 0153 3,913,628

METHOD AND APPARATUS FOR HERMETICALLY SEALING A PACKAGE This is a division of application Ser. No. 141,588, filed May 10, 1971 now U.S. Pat. No. 3,793,688.

This invention relates to the closing and sealing of flexible containers and is more particularly concerned with improvements in a method and an apparatus for forming closure members of bendable metal, or like material, and applying such members to the collapsed mouth end of a flexible bag or casing enclosing a product, such as foodstuff, so as to seal the same.

In one form of packaging which has been used extensively, particularly for packaging foodstuff, the product is placed in a bag formed of flexible plastic film or the like and the mouth of the bag is gathered into a ropelike formation for receiving a seal-forming closure fastener or clip, usually of metal. In the packaging of certain products, for example, cuts of fresh meat or poultry, the bag is vacuumized before the fastener is applied and clinched about the neck material. The package may then be passed through a heat tunnel to shrink the film material. Fasteners and fastener forming and applying machines of various kinds have been designed for use in this type packaging operation. One such machine is disclosed in US. Pat. No. 3,524,242, granted to David J. Odean and Roy E. Wells, which is air powered and hand operated and which is constructed to preform a U-shaped fastener from metal wire, fed from a supply reel, and simultaneously to apply and clinch a previously formed fastener on a gathered bag end, casing, or the like, by wrapping the legs of the same about the gathered material so as to form a tight permanent closure. A general object of the present invention is to provide an improved method and apparatus for forming and applying fasteners of the metal clip type to the gathered neck portion of a filled bag so as to obtain a tight wrapping of the fastener legs about the gathered material.

A more specific object of the invention is to provide an improved method and apparatus for applying a fastener to the gathered neck portion of a filled bag or casing which employs a bendable U-shaped clip-type fastener and wherein the legs of the fastener are wrapped around the gathered material in a manner which results in a tight hermetic seal.

Another object of the invention is to provide a pack aging method and apparatus for forming and applying U-shaped, clip-type, wire metal closure fasteners to the gathered neck portions of filled bags or casings in such a fashion that the legs of the U-shaped fastener are wrapped around the gathered neck material with end portions brought into side-by-side, overlapping, tight engagement so as to effectively seal the bag mouth.

A further object of the invention is to provide a method and apparatus for forming metal clips for application as closure fasteners to gathered neck portions of bags or casings which insures that the ends of the clips do not cut the bag material when applied and that the application of the clip results in a very tight seal.

A still further object of the invention is to provide a generally U-shaped sealing clip of improved form which is readily applied to a gathered bag neck by a specially designed punch and anvil so as to tightly wrap the legs of the clip about the gathered bag material and form an hermetic seal.

These and other objects and advantages of the invention will be apparent from a consideration of the method and apparatus which is described herein and shown, by way of illustration, in the accompanying drawings wherein:

FIG. I is a side elevation, with portions broken away, of an apparatus for forming and applying bendable closure forming wire fasteners to a collapsed bag neck, which apparatus embodies features of the invention;

FIG. 2 is a side elevation of the apparatus of FIG. I, with certain movable members thereon in a different position;

FIG. 3 is a fragmentary cross section taken on the line 3-3 of FIG. I, to an enlarged scale;

FIG. 4 is a fragmentary section taken on the line 4-4 of FIG. 3;

FIG. 5 is a cross section taken on the line 5-5 of FIG. 1, to an enlarged scale;

FIG. 6 is a view showing a portion of the apparatus of FIG. 1 on an enlarged scale;

FIG. 7 is a fragmentary view showing, to a larger scale, a portion of FIG. 6;

FIG. 8 is an exploded perspective view, with portions broken away and other portions omitted, the view showing the fastener forming and applying elements of the apparatus;

FIG. 9 is a fragmentary perspective view showing a portion of the fastener applying punch and the associated clinching anvil with a preformed fastener in position to be applied as a closure fastener to a bag neck;

FIG. 10 is a view showing a fastener element as preformed in the apparatus;

FIG. 11 is a view taken on the line 1l] 1 of FIG. I0, to an enlarged scale; and

FIG. 12 is a fragmentary perspective view showing a portion of a bag neck with a fastener clinched thereon.

Referring to the drawings, there is illustrated a fastener forming and applying apparatus which embodies features of the present invention and which is particularly adapted for use in applying fasteners according to the method of this invention to the gathered neck portion of a bag which has been filled with a product and vacuumized on a semi-automatic vacuum bagging machine of the type shown in application Ser. No. 137,412, filed Apr. 26, 1971, issued Oct. 24, 1972, US. Pat. No. 3,700,387.

The illustrated fastener applying machine comprises a supporting frame 10 which is adapted to be mounted in a generally upright position on the main frame of the bagging machine. The frame 10 has a horizontally extending top leg 12 on the top face of which there is mounted a main cylinder 14 and associated mechanism for driving a depending, vertically reciprocating punch assembly 15. A bottom anvil mechanism 16 is mounted on the base portion 17 of the frame 10 for cooperation with the punch 15 in applying U-shaped fasteners or clips F (FIGS. 6 and 8) to a gathered bag neck. The fasteners F are preformed to a U shape by the clip applying apparatus from wire stock delivered to a wire infeed mechanism which is indicated at 18 (FIG. I). The wire infeed mechanism 18 delivers successive lengths or sections of fastener forming wire W to a preforming anvil 20 on which successive U-shaped clips or fastener elements F are formed by a clip former 21 on the punch assembly 15 while a previously formed fastener F is ap plied to and clinched on the gathered and constricted neck portion N (FIG. 3) of the bag by fastener engaging end 22 on the punch 15.

The punch assembly 15 extends downwardly from and is powered by the main air cylinder 14 mounted at the top of the main frame and controlled by a valve 23 mounted on a bracket member 24 at the upper end of the cylinder 14 and connected to an appropriate compressed air supply. The punch is guided for reciprocation in a generally vertical path in a guideway 25 (FIG. 6) formed in a die block 26 secured on the main frame 10. The punch assembly 15 has a main stem or ram portion with a clip former 21 on the bottom end and a bottom portion 27 secured in depending relation on the stern portion with a fastener engaging and clinching bottom end 22. The clip former 21 has a bottom face shaped to provide a wire cutoff edge 28 (FIG. 8) and a clip preforming die configuration which is spaced a predetermined distance above the bottom end 22 of the punch assembly 15. The fastener applying and clinching lower end section 27 of the punch 15 has a downwardly facing groove 29 (FIGS. 6 and 9) in the clip-engaging bottom end 22 which is semi-circular and which receives the top cross bar forming portion 30 of the U-shaped preformed fastener clip F so as to drive the same through a guideway which is formed in part by a slot 31 in a guide member 32 supported on the lower end of the frame 10 immediately above an anvil insert 33, the latter being seated in a holder 34 having means (not shown) for adjusting the elevation of the insert 33 and forming part of the anvil assembly 16. The guideway for the punch and fastener includes a slot or recess 31 (FIGS. 3 and 8) in the inside face ofa gate 35 (FIGS. 1, 2, 3,) which is pivoted at 36 for swinging movement between a closed position as shown in FIG. 1 and an open position as shown in FIG. 2. The guideway 31, 31 which is generally rectangular in cross section, is in the plane of the guide member 32 and the gate 35 while the faces of these two members which extend vertically in oppositely disposed, confronting relation, when the gate 35 is closed, are at an angle to the plane of the guideway 31, 31' so as to position the gathered bag neck N, with its axis normal to the plane of movement of the legs of the fastener F as the latter is closed about the same by descent of the punch 15.

The gate 35 is mounted on a pivot 36 on the member 32 to swing between an open and closed position and is operated by a vertically disposed air cylinder 40 which has its piston rod 41 connected by pivot 42 to the gate 35 and which is mounted at the upper end by means of the pivot 43 on an angle bracket 44. The bracket 44 is in turn pivoted at 45 to the bracket 24 and urged in a clockwise direction by a compression spring 46 set in the recess 47 in the bracket 24 with the end thereof engaging the upstanding arm of the bracket 44. The bracket 44 carries an adjustable actuating pin 48 for triggering the valve 23 controlling cylinder 14 so that the cylinder 14 is operated by reaction force of the gate closing. The operation of the gate closing air cylinder 40 is controlled by operator actuation of a bump switch on the bagging machine so as to close the gate after the gathered bag mouth has been moved into position above the anvil assembly 16 for the application of the fastener. The valve 23 is closed by a pressure switch (not shown) when the back pressure in the cylinder reaches a predetermined value so as to control the clinching pressure exerted by the punch end 22 in closing the fastener.

The anvil insert 33 is especially constructed for the application of a fastener having legs of sufficient length to wrap around the constricted bag material. The anvil insert 33 has a pair of grooves 50, 50' (FIGS. 3, 4, 6, 8 and 9) which extend in parallel relation in planes which are at an angle of approximately 15 relative to the plane of the insert and the guideway 31, 31 with the grooves being offset relative to the centers thereof in the lengthwise direction and the opposite outer ends being positioned or spaced to receive the ends of the legs 51, 51 of the fastener F. The grooves 50, 50' are curved in cross section and the end portions 52, 52' are curved in the lengthwise direction while there is a short flat or non-curved section or length 53 in the middle of each of the grooves. The construction of the grooves is designed to turn the legs of the fastener inwardly toward each other as the punch 15 descends and to move the ends in parallel, side-by-side relation beneath the constricted bag material and form a tight closure about the same without any cutting or tearing of the bag material.

As each succeeding fastener F is applied and clinched about a bag neck, the next succeeding fastener is formed on the preform block 20. The fastener wire W, which is round and ofa suitable gauge of metal wire stock or other bendable material, is fed in a generally horizontal path to a wire advancing device 18 which comprises wheels 56 and 57 (FIGS. 1 and 5) having cooperating, peripheral wire gripping surfaces between which the wire W is advanced and shaped. The uppermost wheel 56 is mounted on a shaft 58 in the frame 10 and has a generally V-shaped groove 60 in its peripheral face. The lowermost wheel 57 is mounted on a shaft 61 set in a frame 62 which is pivoted at 63 on the main frame 10 and urged in a clockwise direction by the tension spring 64 connected at one end at 65 to the frame 62 and at the other end at 66 to the frame 10. The peripheral surface of the wheel 57 has a groove 67 with a bottom surface 68 which has a cross sectional curvature on a radius larger than the cross section radius of the wire W so as to provide a somewhat flattened area on the wire portion which subsequently engages the bag neck material when a length of the wire is cut off and formed into a fastener F and applied or clinched about the bag neck material. The wire W is advanced between the feed wheels 56 and 57 which shapes the wire as shown in FIG. 5 and advances it through a bushing 70 (FIGS. 6 and 7) of special construction to a position above the preform anvil 20 where a length of the wire sufficient for forming a fastener F is cut off by descent of the punch 15 as shown at L in FIG. 6. The bushing 70 has a bore somewhat larger in diameter than the cross sectional diameter of the wire W and the exit end of the bushing 70 has an inward taper at the approach to the cutoff point as indicated at 71 so that when a length or section L of the wire is cut off by the descent of the punch 15, the bottom edge of the trailing end of the wire length L is drawn towards the center of the wire, as indicated at 72 in FIG. 7, and thereby eliminates any tendency to form a burr thereon, which might subsequently puncture the material when the fastener made therefrom is wrapped about the bag material. The tapered approach section or ramp 71 in the bushing 70 also results in the drawing of the material away from the lower face of the supply end of the wire when the length of wire L is cut off. This prevents the formation of any burr on the leading end of the cutoff length L of the wire which is on the bagengaging, lower side of the fastener element, when the latter is formed into a fastener clip, thereby reducing the likelihood of the ends of the fastener puncturing the bag material in a manner which could cause a leaker when the fastener is applied to a vacuumized bag. This is particularly desirable on the bag body side of the fastener so as to insure that the vacuumized condition of the bag is not lost. The length of wire L is fed beneath a guide pin 74 into proper position on the anvil 20 so that the descent of the preforming die end 21 on the punch assembly severs a wire length L and forms the latter into the U shape desired. The preforming anvil is slidably mounted and spring backed and operates in the same manner as described in US. Pat. No. 3,524,242 to which reference may be had for details of this and other corresponding elements not fully described herein.

The apparatus is provided at the base of the main frame 10 with a double plate guide shoe 75 which is fixed on the frame 10 with a top, upwardly slanting face 76 forming a ramp for guiding the bag neck into proper position on the anvil assembly 16 and against the vertical face of the guide member 32 for closing the gate 35 thereon. A stripper plate assembly 77 is pivoted at 78 on the main frame structure or guide member 32 and spring backed as the corresponding assembly in US. Pat. No. 3,524,242, so as to insure that the bag material is held clear of the anvil as the clip legs pass below and that the clinched bag neck will be released when the punch assembly is retracted upwardly.

The form of the U-shaped fastener F, as shown in FIGS. 10 and 11, is such that the inside surface 80 which engages the bag material is on a shallow, cross sectional curvature with the ends of the legs 51, 51' devoid of sharp edges or burrs so that when the legs are wrapped about the material under the guidance of the grooves 50, 50' in the anvil insert 33 there is no gouging or tearing of the bag material and consequently no leakage when a vacuumized bag is closed by application of the fastener. The cross bar 30 is curved on a relatively large radius so that pressure exerted at the ends of the bar by the engagement of the curved bottom end 22 of the punch 15 need not be as great since the bar 30 is already preformed or precurved to the general shape it will take when the legs 51, 51' are wrapped about the bag neck material and will readily bend to the final shape as determined in part by the bulk of the bag neck material. The resultant closure, as shown in F 1G. 12, provides a uniform tight hermetic seal with allowance for considerable variation in the size of the bag mouth.

We claim:

1. In an apparatus for forming U-shaped fasteners of metal wire for application as closures to the gathered mouth of a flexible packaging container wherein there is provided a forming anvil and a reciprocably mounted, co-operating forming punch with a knife for severing said wire in predetermined lengths, means for feeding said predetermined lengths of wire from a supply source to position the leading end thereof between the forming anvil and the punch which comprises a guide member having therein a wire guiding elongated bore extending from its wire receiving end to adjacent its wire exit end, said member having a surface at its exit end for co-operation with said knife to sever successive lengths of wire of a predetermined length to form the fasteners and a tapered ramp-forming inner surface at the exit end of said sleeve for causing the material at the cutoff point to be drawn toward the center of the wire and thereby eliminate any tendency to form a burr thereon.

2. in an apparatus as set forth in claim 1 wherein said knife forms a part of said punch and said means cooperating with said knife for severing the wire material is an integral part of said guide sleeve. 

1. In an apparatus for forming U-shaped fasteners of metal wire for application as closures to the gathered mouth of a flexible packaging container wherein there is provided a forming anvil and a reciprocably mounted, co-operating forming punch with a knife for severing said wire in predetermined lengths, means for feeding said predetermined lengths of wire from a supply source to position the leading end thereof between the forming anvil and the punch which comprises a guide member having therein a wire guiding elongated bore extending from its wire receiving end to adjacent its wire exit end, said member having a surface at its exit end for co-operation with said knife to sever successive lengths of wire of a predetermined length to form the fasteners and a tapered ramp-forming inner surface at the exit end of said sleeve for causing the material at the cutoff point to be drawn toward the center of the wire and thereby eliminate any tendency to form a burr thereon.
 2. In an apparatus as set forth in claim 1 wherein said knife forms a part of said punch and said means co-operating with said knife for severing the wire material is an integral part of said guide sleeve. 